1. Field of the Invention
The present invention relates to a package module and a method for packaging the same, and particularly relates to a multi-wavelength LED array package module and a method for packaging the same.
2. Description of the Related Art
In the typical printer technology, a laser is used as a light source in a printer head to scan and transfer the printing information as light signals to a rotating drum in order to generate electrostatic latent images formed on the rotating drum. Moreover, the printing method further includes a toner absorbing step, a transferring step, a hot pressing step, an electrostatic discharging step etc. to achieve printing requirement. However, a laser printer head of the prior art has many optical components, and the mechanism of the laser printer head is complex and the optical path of the laser printer head is very longer. Hence, the optical structure is quite complex and difficult to reduce in size for using a laser in this way. Therefore, the current trend is toward using light emitting diodes to replace lasers as the light sources in printer heads, which can simplify the optical structure.
A further requirement is to reduce the volume of each light emitting diode so as to increase the resolution of the printer. More light emitting diodes may be constructed per unit area in the printer head when the volume of each light emitting diode is reduced. According to the typical packaging method, a highly precise packaging apparatus is required to arrange the light emitting diode arrays and the driver integrated circuits so that they are exactly parallel to each other in a printed circuit board. Then, a wire bonding process is performed to form about 5000 wires between the light emitting diode arrays and the driver integrated circuits if the resolution of the printer is 600 dpi (dots per inch) of A4 size paper. The driver integrated circuits drive the light emitting diode arrays through these wires.
A highly exact and dense wire bonding process in the foregoing method increases the difficulty of the packaging process. This reduces the product yield and indirectly raises the manufacturing cost. Moreover, according to the need of high resolution of the printer, the wire bonding process is more difficult due to the more and more small size of the light emitting diodes.